Chemotactic properties and protein of equine uterine fluid.

Forty uterine fluid samples were obtained from 4 mares classified as resistant to uterine bacterial infection. The uterus of each mare was flushed with 50 ml of saline solution during estrus and diestrus of successive estrous cycles. Bacteria or fungi were isolated from 4 samples, and 7 additional samples were obtained from a mare with active intrauterine infection. Fluid volumes obtained during estrus (means = 40.3 +/- 11 ml) tended to be greater than those recovered during diestrus (means = 36.8 +/- 7.9 ml), but the difference was not significant. Concentrations and yields of protein in recovered fluid did not vary significantly with the day of the estrous cycle. Protein concentration was significantly increased in samples from the infected uterus (P = less than 0.001). The ability of uterine fluid samples to attract neutrophils was measured using chemotactic chambers. There was no significant difference between distances migrated by neutrophils toward fluids obtained during estrus or diestrus. Chemotaxis scores tended to be higher with samples from the infected uterus, and the difference was significant for samples from 2 mares. Chemotaxis was neither significantly correlated with protein concentration of uterine fluid, nor with serum estrogens or progesterone.

Intra-aneurysmal pressure measurements in experimental saccular aneurysms in dogs.

Intra-aneurysmal pressure was studied in an experimental model of saccular aneurysm in dogs, using a vein pouch grafted onto a common carotid arterial bifurcation. The mean and the pulse pressures were recorded simultaneously from within the aneurysm and within the common carotid artery, before and after 50% proximal carotid artery stenosis. These experiments were performed under systemic normotension, hypotension, and hypertension. Normal data suggest that mean intracarotid and intra-aneurysmal pressures are similar and relate in a nearly linear fashion to mean arterial pressure. However, after 50% stenosis, the data had a cubic relationship, the reduction of pressure occurring only in the middle range of mean arterial pressure. Both intra-aneurysmal and intracarotid pulse pressures displayed less dependence on mean arterial pressure. However, sigmoid curves also were observed with the pulse pressures after 50% proximal common carotid artery stenosis. In all cases, after 50% stenosis, the rate of increase of the pulse pressures with mean arterial pressure was greater for higher mean arterial pressures. Our preliminary data indicate that a detailed study of intra-aneurysmal pressure and blood flow in relation to systemic variables such as mean arterial pressure, cardiac output, and peripheral resistance may not only suggest improved means of managing patients with intracranial aneurysms, but also may raise the possibility that, under certain conditions, higher intra-aneurysmal pressures may be induced by downstream stenosis.

An acoustic aneurysm-detector.

Intracranial aneurysms have a high prevalence in the adult population; and if they rupture, significant morbidity almost always ensues. However, pulsatile blood flow through aneurysms produces vibrational sound patterns that may be detected extracranially. Thus, an acoustic aneurysm-detector has been developed to detect the sounds produced by intracranial aneurysms prior to rupture. The design is based on the utilization of a hydrophone for signal detection and computational signal processing for signal extraction. Data are examined in the time domain, the frequency domain, and the time-frequency plane. Examples are presented from an animal model and from a patient with a known aneurysm.

Recording and processing aneurysmal vibration signals in dogs.

A specially designed computerized acoustic aneurysm detection system has been developed and used for recording the acoustic signal produced by aneurysms in dogs. Two transducer types, a modified horn-coupled microphone and a microvascular intra-operative Doppler flowmeter have been used. The results show that the aneurysm signal is time-varying and that a stronger vibration signal can be obtained if a proximal stenosis presents. With direct contact recording, the acoustic signals from aneurysms and parent arteries show different characteristics that can be easily distinguished. The aneurysm signals are processed by spectrograms, and a smoothing technique for suppressing noise is introduced.